Oxidation of triclosan by ferrate: reaction kinetics, products identification and toxicity evaluation.
Oxidation of triclosan by ferrate: reaction kinetics, products identification and toxicity evaluation.
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DOI：
10.1016/j.jhazmat.2010.10.106
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发表时间：
2011-02
影响因子：
13.6
通讯作者：
Bin Yang;G. Ying;Jian-Liang Zhao;Li-Juan Zhang;Yi-Xiang Fang;L. Nghiem
中科院分区：
文献类型：
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作者：
Bin Yang;G. Ying;Jian-Liang Zhao;Li-Juan Zhang;Yi-Xiang Fang;L. Nghiem
研究了商品级高铁酸盐（Fe（VI））氧化三氯生的反应动力学，并测定了pH（7.0-10.0）对反应动力学的影响。使用GC-MS和RRLC-MS/MS技术对氧化工艺的中间产物进行表征。采用Pseudokirchneriella subcapitata生长抑制试验研究了三氯生在Fe（VI）氧化过程中毒性的变化。结果表明，三氯生与Fe（VI）反应迅速，表观二级速率常数kapp在pH 7时为754.7M− 1 s − 1。在化学计量比为10：1（Fe（VI）：三氯生）时，可完全去除三氯生。物种特异性速率常数，k，确定与质子化和去质子化三氯生物种的Fe（VI）的反应。中性三氯生的k值为6.7（±1.9）× 102 M − 1 s −1，而阴离子三氯生的k值为7.6（±0.6）× 103 M − 1 s −1。三氯生被Fe（VI）氧化的机理包括醚键断裂和苯氧基自由基加成反应。三氯生的Fe（VI）降解过程中也可能发生偶联反应。总体而言，三氯生的降解过程导致藻类毒性显著降低。毒性试验表明，Fe（VI）本身投加在反应中不抑制绿色藻类的生长。
The oxidation of triclosan by commercial grade aqueous ferrate (Fe(VI)) was investigated and the reaction kinetics as a function of pH (7.0–10.0) were experimentally determined. Intermediate products of the oxidation process were characterized using both GC–MS and RRLC–MS/MS techniques. Changes in toxicity during the oxidation process of triclosan using Fe(VI) were investigated using Pseudokirchneriella subcapitata growth inhibition tests. The results show that triclosan reacted rapidly with Fe(VI), with the apparent second-order rate constant, kapp, being 754.7M−1s−1at pH 7. At a stoichiometric ratio of 10:1 (Fe(VI):triclosan), complete removal of triclosan was achieved. Species-specific rate constants, k, were determined for reaction of Fe(VI) with both the protonated and deprotonated triclosan species. The value of k determined for neutral triclosan was 6.7(±1.9)×102M−1s−1, while that measured for anionic triclosan was 7.6(±0.6)×103M−1s−1. The proposed mechanism for the oxidation of triclosan by the Fe(VI) involves the scission of ether bond and phenoxy radical addition reaction. Coupling reaction may also occur during Fe(VI) degradation of triclosan. Overall, the degradation processes of triclosan resulted in a significant decrease in algal toxicity. The toxicity tests showed that Fe(VI) itself dosed in the reaction did not inhibit green algae growth.